The invention relates to the field of computer applications to simulate and/or control real processes, in particular processes which comprise sequences of discrete events, known as discrete event dynamic systems (DEDS). Such processes occur for example in technical developments as well as in other business activities in the industrial or tertiary sector. Also, the behaviour of distributed applications on the intranet/internet sector, in particular of systems and associated software for electronic commerce, is based on such discrete processes. By means of the invention it can be defined and optimized in a novel way. The resulting process models can be directly applied in a novel way to monitoring and system control.
Similar approaches for computer applications to processes are known from the field of control of industrial production processes, for example in the chemical industry. Such processes are most often describable by systems of equations, in particular differential equations, which are then reflected in a model and used in this way for control purposes. Also, nowadays building control systems are often computerized, and are designed by means of modelling and simulation.
For example, a paper (in several parts) by K. Pearson xe2x80x9cCharacterizing Complicated Systemsxe2x80x9d in SGA Bulletin No. 24 of December 1998, January and February 1999, published by the xe2x80x9cSchweiz. Gesellschaft fxc3xcr Automatik/SGAxe2x80x9d [Swiss Society for Robotics] deals with processes, more precisely with xe2x80x9cmodel-based control . . . , particularly in the area of industrial process control . . . xe2x80x9d. The article mentions a distillation process which can be described by approx. 350 differential equations. Obviously it is not possible to transpose with ease such an approach which is suitable for mathematically describable, continuous processes, to other processes, in particular to discontinuous processes which cannot easily be described mathematically.
U.S. Pat. No. 4,965,742 by Skeirik also describes a process control system where the modular software which implements process monitoring can be revised and altered by the user without interrupting monitoring. This allows flexible and, above all, rapid adaptation of process control to changed environmental conditions. However, this process control is intended for monitoring and controlling an essentially continuous process which, for example, can be mathematically described by a system of equations, if applicable, differential equations. However, such a system is unsuitable for so-called discrete processes, i.e. processes comprising a sequence of discrete events such as business processes, planning processes or development processes. Such processes cannot be controlled and monitored in the known way, and it is hardly possible to use sensors and actuators such as temperature sensors or control valves in a sensible way.
It is thus the object of the present invention to develop, optimize and automate such discrete processes which normally cannot be described by differential equations as is the case with continuous processes, but which instead comprise sequences of discrete elements or steps. Such processes can be quite complicated, as is the case for example in (technical) system sequences in information technology, e.g. in e-commerce. Processes (or sequences) in enterprises and other organisations, with only an indirect relation to technology, also belong to this category.
In summary, it is the object of the invention to provide an information technology system which is able to control, simulate, optimise and/or monitor discrete processes, i.e. sequences of discrete events.
Essentially, the invention can be described as an information technology system to control processes, in particular processes consisting of sequences of discrete events, whereby a process model corresponds to a real process or reflects a real process. The process model and the real process may be coupled using information technology, via at least one interface, preferably a standardized interface. Direct data exchange between the process model and the real process can now take place via this interface. Preferably a common standard format such as XML, a widely-used internet format, is used. Direct coupling using information technology obviates the need for any expensive and thus usually inefficient data conversion.
According to the invention, the process model cannot only be independent of the real process, but it can also be coupled to the real process. The former, i.e. independent operation, renders the system suitable for simulation of process modifications and/or for optimisation of the process; it is particularly advantageous if the real process should not or must not be interrupted. In such a case, process modification in the process model can be checked (without interrupting the real process) and if the modification was found to be successful it can be integrated in whole or in part in the real process by way of the interface.
As already mentioned, the system according to the invention also allows to couple the process model to the continuous real process, in that the process model, controlled via the interface, runs quasi parallel to the real process, i.e. receives relevant system state information. This allows permanent monitoring and control of the active real process. If the interface between the process model and the real process is bi-directional, it is even possible to assert a direct influence on the real process. In this way it is possible for example, for process modifications which have successfully been simulated in the process model, to be directly transferred to the real process, i.e. applied to the real process. Based on the system state at the time and observed input statistics it is also possible in many cases to determine what will happen in the future and what measures will have to be taken to bring about desired results.
For example, the invention may be applied with workflow management systems for which up to now no such closely coupled solutions exist. Such workflow management systems were, for example, described by S. Joosten, G. Aussems, M. Duitshof, R. Huffmeijer and E. Mulder in xe2x80x9cWA-12: An Empirical Study about the Practice of Workflow Managementxe2x80x9d, a research monograph of the University of Twente, ISBN 90-365-0683-2, 1994.
As has already been mentioned, the novel tool can also be used without direct coupling to a real process. Due to its simple and intelligent handling, it provides advantages when compared to known solutions. As will be shown below, in particular its structure and characteristics make it suitable to be transmitted as a so-called applet, if necessary together with the process model, via the internet or via an (enterprise-internal) intranet. The resulting practically instant propagation, adaptation or modification, together with the possibility of simultaneous access, provides entirely new possibilities. In particular the simultaneous and instant propagation or publication, via internet or intranet, of the dynamic models generated, allows completely novel application of information technology within enterprises and administrations. Details are provided in the embodiment of the invention described below.
According to the invention, the process models mentioned are created simply and graphically by connection with arrows, from already existing components and/or so-called standard elements. Such components may for example also be downloaded from an electronic catalogue from the internet or from an intranet. According to the invention, the components always comprise an environment so that they can be animated and thus checked for suitability, prior to their use.
The above-mentioned standard elements, i.e. the base modules for the user, by means of which the user him/herself can create new components, are made from a few fundamental base elements (at present 3 elements), so-called quarks. This significantly simplifies the preparation of customer-specific or application-specific sets or pallets of standard elements, without having to adapt the system itself.
While at present simple but rather academic examples of discrete event dynamic systems (DEDS) are the subject of scientific treatises, nevertheless entire enterprises or even parts thereof cannot be tackled with this theoretical approach, due to their complexities. In addition, for example, examination of enterprise processes is undertaken predominantly by economists who in turn are not particularly familiar with solutions that (technical) robotics has to offer. Thus, the tools in existence today are predominantly documentation aids which can be used to prepare extensive process documentation but which are hardly usable for design, optimization and control of the mentioned closely-coupled information technology systems. In order to analyse and optimise such DEDS systems, theoretically based models thereof, which can be simulated, are required.
The embodiment of the invention described below describes the integration of a new tool according to the invention in a workflow system or ERP (Enterprise Resource Planning) system. Such a tool not only serves to optimise a DEDS process, but also serves as a workflow design and workflow view tool which makes it possible to continuously monitor the system state and/or to adapt the system.